Method of and material for producing multicolor images



July 11, 1939. A A 2,166,049

METHOD OF AND MATERIAL FOR PRODUCING MULTICOLCR IMAGES Filed Nov. 30,1957 l i 4.5UPPORT 1. BLUE SENSITIVE YELLOW FILTER DYE ZGREENSENSiTH/ESILVER HALIDE LA CONTAINING A D YE \lFOR YELLOW 5, RED SENSITWE ZFORMAGENTA FORMING SUBSTANCE anveml'oz BELA 'GASPAR 4 Patented J l 11, 1939Hatfield METHOD OF AND MATERIAL FOR PRODUC- ING MULTICDLOR IMAGES BelaGaspar, Brussels-Forest, Belgium Application November 30, 1937, SerialNo. 177.3%

8 Claims.

The present invention relates to a light sensitive photographic materialcomprising a plurality of superimposed silverhalide layers each of whichis predominantly sensitive to one of the three primary colors blue,green, and red respectively. The materialallows the production ofmulticolor images and is especially suitable for exposures in aphotographic or kinematographic camera.

The light sensitive material is schematically shown in the annexeddrawing, in which the arrangement of the superimposed layers, theirsensltivity and their coloration are indicated. The support 4 formed bya transparent material carries three layers l, 2, 3 in superposition.Layer l which is next to the support is an ordinary blue sensitivesilver halide emulsion and contains a dyestuff forming substance fromwhich a yellow azodyestuff can be produced by appropriate treatment.Layer 2 is formed by an orthochromatic emulsion predominantly sensitiveto green light. This layer contains a dyestufi forming substance capableof being transformed into a magenta azodyestuflf. Layer 3 is formed by ared sensitive silver halide layer. Filter dyestuffs which can be washedout from the layers may be present as well in layer 2, as in layer 3,the filter dyestufl in layer 2 being yellow and the filter dyestuffpresent in layer 3 being red.

In the multilayer material the blue sensitive layer is arranged next tothe support and the material is exposed with the support facing thelight source during exposure or the objective of the camera. Afterexposure the top layer 3 is diffusely colored by a blue-green dyestuff,preferably an azodyestufi. It is recommended to incorporate aprecipitating agent into layer 3 prior to exposure in order toprecipitate and thereby to fix the dyestull when treating the surfacewith the dyestuff solution after exposure, as described in my co-pendingU. S. application Ser. No. 86,427 now Patent No. 2,137,336, Nov. 22,1938.

The dyestufl forming substances present in layers l and 2 aretransformed into dyestuffs after exposure by a process which yields a.yellow dyestuff from the dyestufi forming substance present in layer land a magenta dyestufi from the dyestuff forming substance present inlayer 2. After all of the three layers are diffusely dyed and the silverimages are developed, three part images formed by black silver arepresent, each in one of the three layers. The color selection picturewhich has been obtained by the photographic action of blue light isobtained in the layer diffusely dyed yellow, the color selection pictureobtained by the green light rays is present in the layer diffusely dyedby the magenta dyestufi and the red color selection picture is situatedin the blue-green dyed layer.

The dyestufi in each of the three layers is, thereafter, locallydestroyed at the points where 5 silver is present. Thus a multicolorimage composed of three superimposed differently colored part images andgiving the correct colors of the object photographed is directlyobtained in the recording material.

The light sensitive material and the process described are especiallyadapted for the use of the amateur, because color pictures in the correct colors are directly obtained from the exposed recording material byappropriate treatment. With most of the present materials and processesit is-either necessaryin order to obtain a correct color imageto make asecond print from the image originally obtained which is a negative, orto develop the exposed plate or film by a reversal process to form apositive.

A further advantage of the new recording material results from the factthat the three layers are arranged on that side of the transparentsupport which is remote from the light source or objective duringexposure. Disturbing halation effects are thereby avoided.

The arrangement of the three layers of the new material in which the redsensitive layer is not coated next to the support, but is arranged ontop of the two other layers offers a number of advantages. The qualityof a multicolor image depends to a great extent upon the correctness ofthe blue-green part image. This part image is produced in the top layerof the recording material. As the dyestuff is applied to this layerafter exposure, this material ofiers the advantages that the colorintensity of this layer can easily be corrected by the coloring processand an exact balance between the blue-green dyestuff 40 and thedyestufis produced from the dyestuff forming substances presentin'layers l and 2 can be obtained without diificulty.

The dyestufi forming substances incorporated in layers l and 2 areselected in such way that azodyestuffs of the required color shade canbe simultaneously produced. Either substances which are capable ofcoupling with a diazocompound may be used, or amino-compounds which arecapable of being diazotized and to yield azodyestuffs by coupling.

An exposure material which is to be regarded as an example only of myinvention, may be produced as follows. A transparent support such asglass, Celluloid or cellulose acetate is coated with an ordinary silverhalide emulsion of high sensitivity for blue light. An emulsion may beused which contains about 14 grams gelatine per square meter of thecoating and about 12 to 14 grams silver bromide. Before coating analcoholic solution containing 0.85 g. per sq. meter (grams per squaremeter) emulsion, 1-phenyl-3- methylpyrazolonisadded to the emulsion or aderivative therefrom may be used, for instance, thetriphenylguanidine-salt of the dipyrazolone obtained fromp-aminobenzoyl-p-phenylenediamine-sulphonic acid, according toChemisches Zentralblatt, 1916, Vol. I, page 196. On top of the bluesensitive layer a second layer is coated formed by a silver halideemulsion sensitized by 2 methyl 1 ethylthiopseudocyanine-iodide (Journalof London Chem. Soc. 1928, Vol. 1, page 214) and containing 1 g.1-amino-8-naphthol- 3,6-disulphonic acid or preferably a derivativetherefrom such as carbonyl-ibis- 8-[4-(4-amino-benzamino) benzamino]-naphthol-(1)-disulphonic acid (3 '6) (Bellsteins Handbuch derorganischen Ghemie, 4th ed. 1933', Suppl. Vol. XIV, page 759, formula XIon page 758), calculated per sq. m. of the coating. The sulphonic acidmay be rendered insoluble within the emulsion by the addition of aprecipitating agent such as, for example, triphenylguanidine-acetate.The emulsion is dyed yellow by the addition of 0.75 g. per sq. m. ofTartrazine (Colour Index No. 640). On the top of the second layer asilver halide emulsion layer is coated which is sensitized to red, forexample by Pinacyanole. This layer contains 1 g. diphenyl-guanidineacetate per sq. m. emulsion and may be colored red by a red filter dye.After exposure in the camera the film or plate is developedby a weaklyalkaline developer. As an example of a suitable developer the followingmay be mentioned:

The film or'plate is treated with this developer for about 20 to 25minutes and, thereafter, fixed and washed. Thereafter, the film or plateis treated by a solution containing'a diazonium salt solution such as,for example Diazosulfanilic acid g 0.5 Sodium acetate g Water g 100 Thetemperature of the bath may be chosen between 3 and 8 C. and should notbe higher than about 10 C. The coupling is accomplished after 5 minutes.The treatment results in the formation of yellow dyestuff and a reddyestuff in the two layers I and 2. After a few minutes the film iswashed and dried. The dry film is treated by a blue-green dyestufisolution, for example by a 3% solution of Pontamine Sky Blue (ColourIndex No. 518) which is precipitated in the form of itsdiphenyl-guanidine-salt. After 4 to 6 minutes the intensity of thecolorization may be tested and the coloring process is interrupted assoon as the film as a whole appears in a black or grey color. After ashort treatment with water the film is hardened by a 10% solution ofchromium alum and then the dyestuff is destroyed at the silver points ofall the layersfby acid solution of thiocarbamide containing for exampleThiocarbamide g-.. 3.5 Sulfuric acid conc ccm 0.5 Water ccm 100 Afterabout 10 to 20 minutes the film or plate is removed from the dyestufidestroying bath and the silver is bleached out by cupric chloride toform silver chloride which is dissolved by sodium thiosulfate. V Thefilm is washed and dried.

Instead of the thiocarbamide solution any suitable dye-destroying agentscan be used such as, for instance those described in my U. S. Patent No.2,020,775, Nov. 12, 1935.

Instead of diffusely dyeing the top layer and thereafter destroying thedyestufi locally any other suitable method for producing a colored imagemay be applied to the top layer.

Instead of the dyestuif forming substances used in the example, otherdyestufi forming substances may be used including stablediazo-compounds, phenols, naphthols, aromatic amines, hydrazo-compounds,as for instance described in my prior U. S. Patents Nos. 2,071,688, Feb.3, 1937, 2,041,827, May 26, 1936, and 1,956,017, April 24, 1934.Furthermore, other filter dyestuffs orv other sensitisers may be appliedas is well known in the art. Between the single light sensitive layersthere may be applied layers of plain gelatine either colorless orcontaining filter dyestuffs.

The material described in the present specification is especiallyadapted for the process described in my U. S. Patent No. 2,071,688 butthe dyestufi forming substances described in my U. S. Patent No.2,041,827 may be used instead of the dyestufi forming substancesdescribed in my U. S. Patent No. 2,071,688. a

Furthermore, amino-compounds capable of being diazotized can be usedwithin the three layers of the material, such as for example 0.85 g.Diazo-Light-Yellow 2 G (Colour Index No. 654), may be present in theblue sensitive layer, whereas in the second layer the urea obtained from1-5-naphthylene-diamine may be used, the

third layer in this case being the same as the third layer of theforegoing example. This third layer, however, may also be appliedwithout addition of a precipitating agent. After exposure the threelayer material is developed as described above. Thereafter the film orplate is treated by a solution containing Sodium nitrite; g 1

Sulfuric acid conc ccm 16 Water F liter 1 The temperature of the bathmay be chosen between 3 and 8 C. and should not be higher than about 10'C. The diazotation is accomplished after 10 to 15 minutes. The film iswashed and may be treated for a short time in a 3% solution of urea. Thefilm or plate, thereafter, is treated with a 2% solution of fi-naphtholdissolved in alkali, the solution being as far as possible neutralizedby the addition of acetic acid. The treatment results in the formationof yellow dyestuif and a red dyestufi in the two layers I and 2.

Instead of difiusely dyeing the top layer and thereafter destroying thedyestuff locally any 'other suitable method for producing a coloredimage may be applied to the top layer.

What I claim is: I 1. A light sensitive multi-layer photographicmaterial adapted to be exposed through a transparent support and havingthree light sensitive silver halide emulsion layers applied insuperposition on the same side of the support, only two of the threelayers comprising a dyestuif forming substance for the formation ofazodyes, the light sensitive layer next to the support beingpredominantly sensitive to blue light, the layer between the bluesensitive layer and the third layer being predominantly sensitive togreen light and the layer on the surface of the assembled multi-layermaterial being predominantly sensitive to red light, a dyestufi formingsubstance in the blue sensitive layer capable of forming a yellowazo-dyestufi, a dyestuff forming substance in the green sensitive layercapable of forming a magenta azo-dyestuff, and means for preventingexposure of said red and green sensitive layers by blue light throughsaid support.

2. A light sensitive multi-layer photographic material adapted to, beexposed through a transparent support and having three light sensitivesilver halide emulsion layers applied in superposition on the same sideof the support, only two of the three layers comprising a dyestuffforming substance for the formation of azo-dyes, the light sensitivelayer next to the support being predominantly sensitive to blue light,the layer between the blue sensitive layer and the third layer beingpredominantly sensitive to green light and the layer on the surface ofthe assembled multi-layer material being predominantly sensitive to redlight, a dyestufi forming substance in the blue sensitive layer capableof forming a yellow azo-dyestuff, a dyestuff forming substance in thegreen sensitive layer capable of /-forming a. magenta azo-dyestuff, anda yellow filter dyestuif in said green sensitive layer for preventingexposure of said red and green sensi- 40 tive layers by blue lightthrough said support.

3. A light sensitive multi-layer photographic material adapted to beexposed through a transparent support and having three light sensitivesilver halide emulsion layers applied in superposition on the same sideof the support, only two of the three layers comprising a dyestuflforming substance for the formation of azo-dyes, the light sensitivelayer next to the support being "predominantly sensitive to blue light,the layer between the blue sensitive layer and the third layer beingpredominantly sensitive to green light and the layer on the surface ofthe assembled multi-layer material being predominantly sensitive to redlight, a dyestuff forming substance in the blue sensitive layer capableof forming a yellow azo-dyestufi, a dyestufi forming substance in thegreen sensitive layer capable of forming a magenta azo-dyestufl, meansfor preventing exposure of said red and green sensitive layers by bluelight through said support, and a red filter ,dyestuff in said redsensitive layer for preventing exposure of said red sensitive layer bygreen light through said support.

4. A light sensitive multi-layer photographic material adapted tobeexposed through a transparent support and having three light sensitivesilver halide em sion layers applied in superposition on the same sideof the support, only two of the three layers comprising a dyestuifforming susbtance for the formation of azo-dyes, the light sensitivelayer next to the support being predominantly sensitive to blue light,the layer between the blue sensitive layer and the third \layer beingpredominantly sensitive to green light and the layer on the surface ofthe as sembled multi-layer material being predominantly sensitive, tored light, a precipitating agent capable of forming an insoluble saltwith a blue green dyestuff in said red sensitive layer, a dyestufl'forming substance in the blue sensitive layer capable of forming ayellow azo-dyestufi,

a dyestufi forming substance in the green sensitive layer capable offorming a magenta azodyestufi, and means for preventing exposure of saidred and green sensitive layers by blue light through said support.

5. A light sensitive multi-layer photographic material adapted to beexposed through a transparent support and having three light sensitivesilver halide emulsion layers applied in superposition on the same sideof the support, only two of the three layers comprising a dyestuiiforming substance for the formation of azo-dyes, the light sensitivelayer next to the support being predominantly sensitive to blue light,the layer between the blue sensitive layer and the third layer beingpredominantly sensitive to green light and the layer on the surface ofthe assembled multi-layer material being predominantly sensitive to redlight, a substance in the blue sensitive layer capable of beingtransformed into a yellow azo-dyestuff by coupling with a diazosolution, a substance in the green sensitive layer capable of beingtransformed into a magenta azo dyestufi by coupling with the same diazosolution, and means for preventing exposure of said red and greensensitive layers by blue light through said support.

6. A light sensitive multi-layer photographic material adapted to beexposed through a transparent support and having three light sensitivesilver halide emulsion layers applied in superposition on the same sideof the support, only two of the three layers comprising a dyestuifforming substance for the formation of azo-dyes, the light sensitivelayer next to the support being predominantly sensitive to blue light,the layer between the blue sensitive layer and the third layer beingpredominantly sensitive to green light and the layer on the surface ofthe assembled multilayer material being predominantly sensitive to redlight, an amino-compound in the blue sensitive layer capable ofbeingdiazotized to yield a diazo compound which will form a yellowdyestuif with an azo dye coupler, an amino-compound in the greensensitive layer capable of being diazotized to form a diazo compoundcapable 'of yielding a magenta dyestufi by coupling with the same azodye coupler, and means for preventing exposure of said red and greensensitive v layers by blue light through said support.

'7. A process of producing multi-coior images which comprises exposing aphotographic material having three light sensitive silver halideemulsion layers applied in superposition on the same side of atransparent support through said support, only two of the three layerscomprising a dyestuif forming substance for the formation of azo dyes,the light sensitive layer next to the support being predominantlysensitive to blue light, the layer between the blue sensitive layer andthe third layer being predominantly sensitive to green light and thelayer on the surface of the assembled multi-layer material beingpredominantly sensitive to red light, a dyestufi forming substance inthe blue sensitive layer capable of forming a yellow azo dyestuiI, adyestuil' forming substance in the green sensitive layer capable offorming a magneta azo-dyestuif, said material including a filterdyestuflf for preventing exposme of said red and green sensitive layersby blue light through said support, developing the latent images,transforming the dyestuif forming substance into azo (lyestufis, dyeingthe top layer of the material with a blue green dyestufi and thereafterdischarging the dyestufis at the points where silver is present.

8. The process of producing multi-color images which comprises exposinga photographic material having three light sensitive silver halideemulsion layers applied in superposition on the same side of atransparent support through said support, only two of the three layerscomprising a dyestufi forming substance for the formation of azo dyes,the light sensitive layer next to the support being predominantlysensitive to blue light, the layer between the blue sensitive layer andthe third layer being predominantly sensitive to green light and thelayer on the suriaoe oi the assemhled multi-layer material heingpredominantly sensitive to reel light an areaozo amino-compound in theblue sensitive layer capable ofbeing (iiazotized to form a diazocompound which may be coupled with an aao coupier to form a yellow azodye, an amino-compound in the green sensitive layer capable of beingdiazotizeol to form a diazo compound which may be coupled with the sameazo coupler to form a magenta azo dye, saiol material including a filterdyestufi ior preventing exposure of said red and. green sensitive layersby blue light through said support, developing the latent images,treating with a diazotizing solution to transform said amino-compoundsto diazo compounds, treating the material with a solution of an azocoupler to produce azo dyestufiis in saiol' Ernie (unseen.

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